Eliminating the picket fence effect of the fast Fourier transform

Li, Yan Feng; Chen, Kui Fu

doi:10.1016/j.cpc.2007.11.005

Cited by 57 publications

(33 citation statements)

References 13 publications

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“…The Newton's iteration was repeated until the difference between two successive approximations of the function value was below 10 −6 . The DFT analysis was performed in MATLAB using function FFT [19]. For DFT, sampling frequency was 100 kHz, input signal frequency was 1 kHz and number of samples was 100.…”

Section: Results ---Harmonic Distortionmentioning

confidence: 99%

“…Also, the length of the sequence N divided by the time-period of the each analysed frequency component in spectrum must be an integer number, to avoid spurious components and influence of the picket-fence effect [19,20]. The values of the time-domain sequence have to be calculated iteratively, using Newton's method for each point f (nT ).…”

Section: Numerical Fourier Analysismentioning

confidence: 99%

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Modelling of Non–Linear Distortion in Vacuum Triodes Using Trans–Characteristics Inverse and Newton’s Method

Dadić¹

2013

Journal of Electrical Engineering

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The increased interest in vacuum tube audio amplifiers led to an increased interest in mathematical modelling of such kind of amplifiers. The main purpose of this paper is to develop a novel global numerical approach in calculation of the harmonic distortion (HD) and intermodulation distortion (IM) of vacuum-triode audio amplifiers, suitable for applications using brute-force of modern computers. Since the 3/2 power law gives only the transcharacteristic inverse of a vacuum triode amplifier, unknown plate currents are determined in this paper iteratively using Newton’s method. Using the resulting input/output pairs, harmonic distortions and intermodulations are calculated using discrete Fourier transform and three different analytical methods.

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Section: Results ---Harmonic Distortionmentioning

confidence: 99%

Section: Numerical Fourier Analysismentioning

confidence: 99%

Modelling of Non–Linear Distortion in Vacuum Triodes Using Trans–Characteristics Inverse and Newton’s Method

Dadić¹

2013

Journal of Electrical Engineering

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“…An accurate frequency estimate can be obtained after two or three iterations. Moreover, incorrect polarity estimation (IPE) [14,16,35] can almost be completely avoided in the proposed algorithm.…”

Section: * Corresponding Authormentioning

confidence: 97%

Frequency estimation of the weighted real tones or resolved multiple tones by iterative interpolation DFT algorithm

Luo

Xie

2015

Digital Signal Processing

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“…Although it produces satisfactory results, the FT based method is subject to a number of generic limitations: aliasing [5], spectral leakage [6,7] and picket-fence effect [5,8]. Especially the latter two often lead to significant errors in spectrum estimation so that the weak signature due to faults in signals cannot be resolved properly for accurate fault detection and diagnosis.…”

Section: Introductionmentioning

confidence: 99%

“…Especially the latter two often lead to significant errors in spectrum estimation so that the weak signature due to faults in signals cannot be resolved properly for accurate fault detection and diagnosis. Although many methods have been developed to improve the limitations [5][6][7][8], they have never eliminated them completely. In addition, the computation complexity is also high which limits its application in real-time condition monitoring.…”

Section: Introductionmentioning

confidence: 99%

Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

Zhen

Wang

et al. 2013

Mechanical Systems and Signal Processing

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Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency components with the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal, allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time domain in comparison with conventional FT based methods.

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Eliminating the picket fence effect of the fast Fourier transform

Cited by 57 publications

References 13 publications

Modelling of Non–Linear Distortion in Vacuum Triodes Using Trans–Characteristics Inverse and Newton’s Method

Modelling of Non–Linear Distortion in Vacuum Triodes Using Trans–Characteristics Inverse and Newton’s Method

Frequency estimation of the weighted real tones or resolved multiple tones by iterative interpolation DFT algorithm

Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

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